Ultrasonographic Monitoring of Follicular Development, Ovulation and Corpora lutea Formation in a Bitch
Follicular development, ovulation and corpora lutea formation in a bitch were monitored daily by ultrasonography using a 8-MHz linear transducer. These findings were compared with vaginal cytology and changes in the peripheral serum concentrations of oestradiol-17b and progesterone. The follicles were identified as anechoic spherical structures on day 6 of prooestrus. The numbers of follicles imaged on day 6 of prooestrus were 3 on the left ovary and 3 on the right ovary. The average follicular size was 0.67 ± 0.06 cm on the right ovary and 0.48 ± 0.02 cm on the left ovary during the follicular phase. Apparent ovulation was characterised by rapid disappearance of the anechoic antrum in both ovaries within 24 h. This finding corresponded to progressive obliteration of the anechoic region and was characteristic for the postovulatory corpora lutea in both ovaries. Corpora lutea were seen as structures containing anechoic lumen of 3.5-4 mm and thick walls. In conclusion, ultrasonographic findings related to cyclic changes in the ovaries agreed with hormonal and vaginal cytological data on the bitch.
Ultrasonographic Monitoring of Follicular Development, Ovulation and Corpora lutea Formation in a Bitch
Follicular development, ovulation and corpora lutea formation in a bitch were monitored daily by ultrasonography using a 8-MHz linear transducer. These findings were compared with vaginal cytology and changes in the peripheral serum concentrations of oestradiol-17b and progesterone. The follicles were identified as anechoic spherical structures on day 6 of prooestrus. The numbers of follicles imaged on day 6 of prooestrus were 3 on the left ovary and 3 on the right ovary. The average follicular size was 0.67 ± 0.06 cm on the right ovary and 0.48 ± 0.02 cm on the left ovary during the follicular phase. Apparent ovulation was characterised by rapid disappearance of the anechoic antrum in both ovaries within 24 h. This finding corresponded to progressive obliteration of the anechoic region and was characteristic for the postovulatory corpora lutea in both ovaries. Corpora lutea were seen as structures containing anechoic lumen of 3.5-4 mm and thick walls. In conclusion, ultrasonographic findings related to cyclic changes in the ovaries agreed with hormonal and vaginal cytological data on the bitch.
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- Length/width (cm)Length/width (cm) Right Left Follicular phase (days –3 to 0) 37 ± 0.02/1.08 ± 0.02 67 ± 0.06 48 ± 0.02 Ovulation (days 0) 41/1.13 Luteal phase (days 1 to 18) 50 ± 0.05/1.12 ± 0.03 59 ± 0.01 56 ± 0.02